Yeah I'm not sure how this is supposed to work. Part of good game design is building intuitive game controls.
Even in the tutorial it is unclear how to progress. It says to click a spot, which that works. It then says click and hold to choose the angle, okay. But then when you release the mouse button, nothing happens. Or if you click madly, nothing happens. And I think one time I hit the ball but I have no idea how. And *this* is what is wrong with this game.
It should not be this hard to figure out how to hit a tennis ball.